ENHANCED IRRADIATION SELF-CROSS-LINKING AND CO-CROSS-LINKING WITH NITRILE RUBBER OF POLY(VINYL CHLORIDE) WITH PENDENT N,N-DIETHYLDITHIOCARBAMATE GROUPS

In order to realize the self-crosslinking of poly(vinyl chloride) (PVC ) and the co-crosslinking of PVC with nitrile rubber (NBR) under UV li ght irradiation, PVC with pendent N,N-diethyldithiocarbamate groups (P VC-SR) was prepared through the reaction of PVC with sodium N,N-diethy ldithiocarbamate in butanone and was then used to enhance the crosslin king reactions. The effects of UV irradiation time, ambient temperatur e, PVC-SR functionality and the mixing ratios of PVC-SR/NBR on the deg ree of gel were investigated and the products were characterized by FT -IR spectra, UV spectra and DSC. The results showed that PVC-SR and th e blends of PVC-SR with NBR easily self-crosslinked and co-crosslinked , respectively, under UV irradiation. However, these reactions did not happen for either PVC, NBR or the blends of PVC with NBR, i.e. the in troduction of N,N-diethyldithiocarbamate groups effectively enhanced t he irradiation crosslinking. The UV spectrum showed that PVC-SR dissoc iated into macromolecular side-chain sulfur radicals and these radical s resulted in crosslinking reactions. (C) 1997 Elsevier Science Ltd. A ll rights reserved.